Device Metadata Cache

jhartleycaw · Fri May 15, 2020 9:08 am

Good morning,

We are lab testing Virtual SAN in Async mode, and have found an issue that we can't explain.

We have created a new image, of around 8TB in a target, then we try and Asynchronous Replicate to another server, and it tells us we need more RAM than the server has to complete. The not enough memory for Device Metadata Cache error. 37GB needed, only have 22 available on the target ASync server.

I know there is overhead, x amount of RAM x TB, on dedup in lsfs, but we are not using lsfs, this is just a thick provisioned image. I think I have 1GB of device ram cache in write through set.

Am I missing something here?

Thanks

James

Fri May 15, 2020 1:48 pm

Hi jhartleycaw,

Welcome to StarWind Forum.
There is a huge overhead I'd say. I do not recommend to use async replication due to notoriously known LSFS overprovisioning.
Learn more about asynchronous replication requirements https://www.starwindsoftware.com/resour ... -recovery/ and https://knowledgebase.starwindsoftware. ... scription/.
Please make sure that you have enough RAM and storage in your servers.